silver trifluoroacetate; silica gel in ethyl acetate T=50°C; Wolff rearrangement; 0.25 h;

silver trifluoroacetate Wolff rearrangement;

1: 74 percent / HCl(g) / diethyl ether; tetrahydrofuran / 0.25 h / 5 °C 2: 1.) 5.6N HBr/AcOH, 2.) N-ethyl-morpholine / 1.) 5min, 2.) DMF 3: 72 percent / N-ethylmorpholine, isobutyl chloroformate / tetrahydrofuran / -15 - 20 °C 4: 6.2N HCl / dioxane / 1 h View Scheme